2
|
Seddik A, Geerke DP, Stockner T, Holy M, Kudlacek O, Cozzi NV, Ruoho AE, Sitte HH, Ecker GF. Combined Simulation and Mutation Studies to Elucidate Selectivity of Unsubstituted Amphetamine-like Cathinones at the Dopamine Transporter. Mol Inform 2016; 36. [PMID: 27860344 DOI: 10.1002/minf.201600094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/23/2016] [Indexed: 11/09/2022]
Abstract
The dopamine and serotonin transporter proteins (DAT, SERT) play a vital role in behavior and mental illness. Although their substrate transport has been studied extensively, the molecular basis of their selectivity is not completely understood yet. In this study, we exploit molecular dynamics simulations combined with mutagenesis studies to shed light on the driving factors for DAT-over-SERT selectivity of a set of cathinones. Results indicate that these compounds can adopt two binding modes of which one is more favorable. In addition, free energy calculations indicated the substrate binding site (S1) as the primary recognition site for these ligands. By simulating DAT with SERT-like mutations, we hypothesize unsubstituted cathinones to bind more favorably to DAT, due to a Val152 offering more space, as compared to the bulkier Ile172 in SERT. This was supported by uptake inhibition measurements, which showed an increase in activity in SERT-I172V.
Collapse
Affiliation(s)
- Amir Seddik
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, 1090, Vienna, Austria
| | - Daan P Geerke
- AIMMS Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical Sciences, VU University, De Boelelaan 1083, 1081, HV Amsterdam, the Netherlands
| | - Thomas Stockner
- Medical University of Vienna, Institute of Pharmacology, Center for Physiology and Pharmacology, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Marion Holy
- Medical University of Vienna, Institute of Pharmacology, Center for Physiology and Pharmacology, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Oliver Kudlacek
- Medical University of Vienna, Institute of Pharmacology, Center for Physiology and Pharmacology, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Nicholas V Cozzi
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706
| | - Arnold E Ruoho
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706
| | - Harald H Sitte
- Medical University of Vienna, Institute of Pharmacology, Center for Physiology and Pharmacology, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Gerhard F Ecker
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, 1090, Vienna, Austria
| |
Collapse
|
3
|
Sandtner W, Stockner T, Hasenhuetl PS, Partilla JS, Seddik A, Zhang YW, Cao J, Holy M, Steinkellner T, Rudnick G, Baumann MH, Ecker GF, Newman AH, Sitte HH. Binding Mode Selection Determines the Action of Ecstasy Homologs at Monoamine Transporters. Mol Pharmacol 2015; 89:165-75. [PMID: 26519222 DOI: 10.1124/mol.115.101394] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/23/2015] [Indexed: 11/22/2022] Open
Abstract
Determining the structural elements that define substrates and inhibitors at the monoamine transporters is critical to elucidating the mechanisms underlying these disparate functions. In this study, we addressed this question directly by generating a series of N-substituted 3,4-methylenedioxyamphetamine analogs that differ only in the number of methyl substituents on the terminal amine group. Starting with 3,4-methylenedioxy-N-methylamphetamine, 3,4-methylenedioxy-N,N-dimethylamphetamine (MDDMA) and 3,4-methylenedioxy-N,N,N-trimethylamphetamine (MDTMA) were prepared. We evaluated the functional activities of the compounds at all three monoamine transporters in native brain tissue and cells expressing the transporters. In addition, we used ligand docking to generate models of the respective protein-ligand complexes, which allowed us to relate the experimental findings to available structural information. Our results suggest that the 3,4-methylenedioxyamphetamine analogs bind at the monoamine transporter orthosteric binding site by adopting one of two mutually exclusive binding modes. 3,4-methylenedioxyamphetamine and 3,4-methylenedioxy-N-methylamphetamine adopt a high-affinity binding mode consistent with a transportable substrate, whereas MDDMA and MDTMA adopt a low-affinity binding mode consistent with an inhibitor, in which the ligand orientation is inverted. Importantly, MDDMA can alternate between both binding modes, whereas MDTMA exclusively binds to the low-affinity mode. Our experimental results are consistent with the idea that the initial orientation of bound ligands is critical for subsequent interactions that lead to transporter conformational changes and substrate translocation.
Collapse
Affiliation(s)
- Walter Sandtner
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Peter S Hasenhuetl
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - John S Partilla
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Amir Seddik
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Yuan-Wei Zhang
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Jianjing Cao
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Marion Holy
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Thomas Steinkellner
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Gary Rudnick
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Michael H Baumann
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Gerhard F Ecker
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Amy Hauck Newman
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology (W.S., T.Sto., P.S.H., M.H., T.Ste., H.H.S.) and Center for Addiction Research and Science (H.H.S.), Medical University of Vienna, Vienna, Austria; Designer Drug Research Unit (J.S.P., M.H.B.) and Medicinal Chemistry Section (J.J.C., A.H.N.), Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria (A.S., G.F.E.); and Department of Pharmacology, Yale University, New Haven, Connecticut (Y.-W.Z., G.R.)
| |
Collapse
|
4
|
Saha K, Partilla JS, Lehner KR, Seddik A, Stockner T, Holy M, Sandtner W, Ecker GF, Sitte HH, Baumann MH. 'Second-generation' mephedrone analogs, 4-MEC and 4-MePPP, differentially affect monoamine transporter function. Neuropsychopharmacology 2015; 40:1321-31. [PMID: 25502630 PMCID: PMC4397398 DOI: 10.1038/npp.2014.325] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/07/2014] [Accepted: 11/09/2014] [Indexed: 11/09/2022]
Abstract
The nonmedical use of synthetic cathinones is increasing on a global scale. 4-Methyl-N-methylcathinone (mephedrone) is a popular synthetic cathinone that is now illegal in the United States and other countries. Since the legislative ban on mephedrone, a number of 'second-generation' analogs have appeared in the street drug marketplace, including 4-methyl-N-ethylcathinone (4-MEC) and 4'-methyl-α-pyrrolidinopropiophenone (4-MePPP). Here we characterized the interactions of 4-MEC and 4-MePPP with transporters for 5-HT (SERT) and dopamine (DAT) using molecular, cellular, and whole-animal methods. In vitro transporter assays revealed that 4-MEC displays unusual 'hybrid' activity as a SERT substrate (ie, 5-HT releaser) and DAT blocker, whereas 4-MePPP is a blocker at both transporters but more potent at DAT. In vivo microdialysis experiments in rat brain demonstrated that 4-MEC (1-3 mg/kg, i.v.) produced large increases in extracellular 5-HT, small increases in dopamine, and minimal motor stimulation. In contrast, 4-MePPP (1-3 mg/kg, i.v.) produced selective increases in dopamine and robust motor stimulation. Consistent with its activity as a SERT substrate, 4-MEC evoked inward current in SERT-expressing Xenopus oocytes, whereas 4-MePPP was inactive in this regard. To examine drug-transporter interactions at the molecular level, we modeled the fit of 4-MEC and 4-MePPP into the binding pockets for DAT and SERT. Subtle distinctions in ligand-transporter binding were found that account for the differential effects of 4-MEC and 4-MePPP at SERT. Collectively, our results provide key information about the pharmacology of newly emerging mephedrone analogs, and give clues to structural requirements that govern drug selectivity at DAT vs SERT.
Collapse
Affiliation(s)
- Kusumika Saha
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Vienna, Austria
| | - John S Partilla
- Designer Drug Research Unit (DDRU), Intramural Research Program (IRP), NIDA, NIH, Baltimore, MD, USA
| | - Kurt R Lehner
- Designer Drug Research Unit (DDRU), Intramural Research Program (IRP), NIDA, NIH, Baltimore, MD, USA
| | - Amir Seddik
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Thomas Stockner
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Vienna, Austria
| | - Marion Holy
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Vienna, Austria
| | - Walter Sandtner
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Vienna, Austria
| | - Gerhard F Ecker
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Harald H Sitte
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Vienna, Austria,Medical University of Vienna, Center for Addiction Research and Science, Vienna, Austria
| | - Michael H Baumann
- Designer Drug Research Unit (DDRU), Intramural Research Program (IRP), NIDA, NIH, Baltimore, MD, USA,Designer Drug Research Unit, IRP, NIDA, NIH, DHHS, 333 Cassell Drive, Suite 4400, Baltimore, MD 21224, USA, Tel: +1 443 740 2660, Fax: +1 443 740 2241, E-mail:
| |
Collapse
|
5
|
Hofmaier T, Luf A, Seddik A, Stockner T, Holy M, Freissmuth M, Ecker GF, Schmid R, Sitte HH, Kudlacek O. Aminorex, a metabolite of the cocaine adulterant levamisole, exerts amphetamine like actions at monoamine transporters. Neurochem Int 2013; 73:32-41. [PMID: 24296074 PMCID: PMC4077236 DOI: 10.1016/j.neuint.2013.11.010] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 11/22/2013] [Accepted: 11/24/2013] [Indexed: 11/17/2022]
Abstract
We quantified adulterants in street drugs sold as cocaine. We analyzed effects of the most common adulterant levamisole, on neurotransmitter transporters. Differences in the selectivity of levamisole can be explained by homology modelling and docking. Aminorex, a metabolite of levamisole, modulates neurotransmitter transporters directly. Depending on the transporter, aminorex acts as a blocker or as a releaser.
Psychostimulants such as amphetamine and cocaine are illicitly used drugs that act on neurotransmitter transporters for dopamine, serotonin or norepinephrine. These drugs can by themselves already cause severe neurotoxicity. However, an additional health threat arises from adulterant substances which are added to the illicit compound without declaration. One of the most frequently added adulterants in street drugs sold as cocaine is the anthelmintic drug levamisole. We tested the effects of levamisole on neurotransmitter transporters heterologously expressed in HEK293 cells. Levamisole was 100 and 300-fold less potent than cocaine in blocking norepinephrine and dopamine uptake, and had only very low affinity for the serotonin transporter. In addition, levamisole did not trigger any appreciable substrate efflux. Because levamisole and cocaine are frequently co-administered, we searched for possible allosteric effects; at 30 μM, a concentration at which levamisole displayed already mild effects on norepinephrine transport it did not enhance the inhibitory action of cocaine. Levamisole is metabolized to aminorex, a formerly marketed anorectic drug, which is classified as an amphetamine-like substance. We examined the uptake-inhibitory and efflux-eliciting properties of aminorex and found it to exert strong effects on all three neurotransmitter transporters in a manner similar to amphetamine. We therefore conclude that while the adulterant levamisole itself has only moderate effects on neurotransmitter transporters, its metabolite aminorex may exert distinct psychostimulant effects by itself. Given that the half-time of levamisole and aminorex exceeds that of cocaine, it may be safe to conclude that after the cocaine effect “fades out” the levamisole/aminorex effect “kicks in”.
Collapse
Affiliation(s)
- Tina Hofmaier
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
| | - Anton Luf
- Clinical Department of Laboratory Medicine, Medical University of Vienna, Waehringer Guertel 10-20, 1090 Vienna, Austria
| | - Amir Seddik
- University of Vienna, Department of Medicinal Chemistry, Althanstrasse 14, 1090 Vienna, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
| | - Marion Holy
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
| | - Gerhard F Ecker
- University of Vienna, Department of Medicinal Chemistry, Althanstrasse 14, 1090 Vienna, Austria
| | - Rainer Schmid
- Clinical Department of Laboratory Medicine, Medical University of Vienna, Waehringer Guertel 10-20, 1090 Vienna, Austria
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria.
| | - Oliver Kudlacek
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
| |
Collapse
|